Facile design and fabrication of RP/ZnIn2S4 composite photocatalysts with efficient removal of antibiotics under visible-light irradiation

Abstract

Efficient photocatalysts with visible light irradiation have a bright future in practical environmental remediation. ZnIn2S4 is a promising environmentally friendly visible-light photocatalyst, due to its appropriate narrow band gap and excellent chemical stability. In this research, the RP/ZnIn2S4 composites with flower spheroidal morphology were synthesized by loading RP onto the surface of ZnIn2S4 via a one-pot hydrothermal process. The experimental results show that the tetracycline (TC) degradation efficiency of RP(1 wt%)/ZnIn2S4 was up to 85.1 %, compared with pure RP, ZnIn2S4, and other series of RP/ZnIn2S4 composites. The optimal degradation conditions were as following: 1 wt% RP modification amount, 30 mg catalyst amount, 30 mg/L initial TC solution concentration, and the initial reaction pH of 7. At the same time, good repeatability and stability of RP(1 wt%)/ZnIn2S4 toward TC removal confirm its potential value for practical applications. In addition, the degradation efficiency of RP(1 wt%)/ZnIn2S4 for rifamycin and ofloxacin under the similar conditions was 80.2 % and 65.3 %, respectively, indicating the universal application of RP/ZnIn2S4 for degradation of different antibiotic pollutants. The possible photocatalytic mechanism was proposed based on the trapping experiment and ESR test. The RP(1 wt%)/ZnIn2S4 composite photocatalytic materials with high efficiency and stability are expected to contribute to the exploration of the environmental protection field.